Chichen Itza (Wikipedia) is one of the largest and most significant Mayan sites in Mexico. El Castillo (the Castle) is a 30m high pyramid and temple that is the focal point of the site. At the spring and autumn equinox, the rising and setting sun hits the corner of the pyramid to form a shadow resembling a serpent. Climbing such pyramids is not for the faint-hearted, and El Castillo has been closed to tourists since 2006 when somebody fell to their death. Between approximately AD 600 and AD 1000 Chichen Itza dominated social, political and economic aspects of…